Electrical contact-point



(No Model.)

B. T. GILLILA-ND.

ELECTRICAL CONTACT POINT.

No. 324,678. Patented Aug. 18, L885.

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EZRA T. GTLLILAND, OF BOSTON, MASSACHUSETTS.

ELECTRICAL CONTACT-POINT.

SPECIFICATION forming part of Letters Patent No. 324,678, dated August 18, 1885.

- Application filed May 15, 1885.

To all whom it may concern:

Be it known that I, EZRA T. GILLILAND, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented certain Improvements in Electrical Contact-Points, of which the following is a specification.

My invention relates to electrical contactpoints for divided electrical circuits, as employed in telephonic and other electrical instruments. These electrical contacts as usually constructed are of two classes. In one form the two points are simply brought to gether and there held by springpressure or an equivalent. In the other, called the sliding contact, one point, before coming to rest, slides or scrapes along upon the surface of the second. Both forms are defective, as the interposition of dust and other insulating substances is not prevented, and this often results in a complete failure in the operation of instruments depending thereon. In telephonic apparatus as at present constructed for public use those defects in contact-points or circuit-closers frequently cause the telephone set to become inoperative. To the end that these difficulties may be remedied, I have-invented improved contact-points or eircuitclosers for use on the switch-arm employed in telephone outfits.

The improvement consists in providing one contact-point or electrode with one or more points or projections placed in position to precede the cont-actpoint proper in a movement across the face of its complementary electrode, thus scraping and cleaning the surface of such electrode and preparing a clean surface upon which the contact-point proper may rest. The two contactpoints are formed of metal or other good conductor. The additional points or projections may be of the same material or not.

The aceon'ipanying drawings illustrate the invention.

Figure 1 shows a magneto-generator and bell having a gravity switch-arm to which my improved contact-points are applied. Fig. 2 is a detached view of the gravity-arm and contact-points in their relative position.

Magneto bell sets for telephonic purposes (No model.)

are usually equipped with four circuitelosing points. I will illustrate my invention by reference to one point, as they are all substantially alike. One cont-act or electrode of a pair is preferably fixed, and consists of a spring, 8, curved at the point of contact with its complementary electrode, a. I construct this electrode a in two divisions, or I form it with two or more edges, corners, or projections, or place one or more points or projections beside the contact-point proper, preceding it in the line of movement imparted to it by the movable support G, so that one or more edges or projections pass across the face of contact 8 at every movement of the support. A very effective construction is shown in the drawings, where the contact a is cylindrical, and has asegment removed from its periphery, forming two sharp edges or projections, b c. WVhen thesupport G is at its lowest extremity, a and s are completely separated; but as support G moves toward its upper limit the edge I) of electrode a first scrapes or brushes the surface of electrode 8, and the edge 0, fol-' lowing 1), takes up its position on surfaces, thus cleaned by the edge or projection. Z) preceding it. Thus any dust or dirt settling upon s is scraped or brushed from its surface and carried out of reach of the edge or contact proper, c.

What I claim, and desire to secure by Let ters Patent, is-

1. The combination of a fixed contact-point and a contact-point having two or more edges or projections located upon a switch-arm in position to slide or scrape across or upon. the surface of the first-named contact whenever said arm is actuated.

2. A fixed contact point or projection and a contact point or projection located upon a movable arm, combined with one or more additional points or projections, also placed in said movable arm in position to precede the contact-point in its movement across or upon the face of the fixed point or projection, so as to brush or scrape the surface of the latter.

3. A magnetogenerator having a movable switch-arm provided with one or more pairs of contact-points, composed of a fixed point name to this specification, in the presence of or surface, and a point or projection located two subscribing witnesses, this 13th day of upon the said arm, combined with one or more May, 1885.

points or projections preceding the last-named EZRA 'l; GILLILAND. 5 contact in its movement upon or across the Witnesses:

face of the fixed point. WM. B. VANsIZE,

In testimony whereof I have signed my GEO. VVILLIs PIERCE. 

